Effects of Atorvastatin on Carotid Atherosclerotic Plaques: A Randomized Trial for Quantitative Tissue Characterization of Carotid Atherosclerotic Plaques with Integrated Backscatter Ultrasound

Abstract

Background: Instability of carotid plaques has been reported to be associated with stroke and other cerebrovascular events. The purpose of this study was to examine whether cholesterol-lowering therapy with atorvastatin in nonhypercholesterolemic patients reduces carotid plaque instability as assessed by ultrasound integrated backscatter (IBS) analysis. Methods: Consecutive non- or slightly hypercholesterolemic patients with moderate carotid artery stenosis were randomly assigned to a diet group (n = 20) or a statin group (atorvastatin; n = 20). Carotid plaques were monitored by measuring intima media thickness (IMT) and IBS values at baseline and after 6 months. Results: Three-dimensional IBS imaging showed that relative lipid volume of carotid plaques significantly decreased from 58.4 ± 25.6 to 47.8 ± 23.5% in the statin group (p < 0.01), whereas there was no significant decrease in the diet group. Significant regression of IMT was not observed in either group. The changes of IBS values and relative lipid volume between baseline and 6 months were correlated with the change in low-density lipoprotein cholesterol (r = 0.31, p < 0.05, and r = 0.34, p < 0.05, respectively). Conclusions: Lipid-lowering therapy by atorvastatin decreased relative lipid volume without significant regression of plaque volume during short-term follow-up in patients with moderate carotid artery stenosis. Quantitative assessment of carotid plaques by IBS analysis was clinically useful for monitoring atherosclerotic lesions.